The invention is a coating, particularly useful for ceiling panels. Advantageously, the coating can be sprayed onto the panel, and furthermore, can be put on and dried to obtain a substantially thick coating without cracking.
U.S. Pat. No. 4,456,507 discloses a method of applying aqueous chip resistant coating compositions. The composition includes a film forming latex binder and a filler mixed with the binder to form a composition having a viscosity of at least 5,000 centipoise. Preferably, the chip resistant coating will be applied by spraying techniques, and the coating will preferably have a binder:filler ratio ranging from 10 to 90% binder:90-10% filler and will exhibit a viscosity of at least 10,000 centipoise. Calcium carbonate may be used as a filler. The coating has an extremely high solid content (70-90%).
U.S. Pat. No. 4,413,026 discloses a composition for coating surfaces such as roofs and the like. The composition includes about 40 to 80% by volume of particles of polystyrene foam plastic particles, in a mixture with about, correspondingly, 60 to 20% by volume of an aqueous synthetic. resin latex. Example I shows use of ground limestone as a filler. Shrinkage due to evaporating is usually much less than 10%. A final blend is coated on a roof at a thickness of 0.25xe2x80x3.
U.S. Pat. No. 4,559,377 discloses a ceiling board coating. The coating includes about 10 to 30, preferably 15.3, weight percent acrylic latex. The coating also includes one or more particulate fillers selected from a, group consisting of clay, such as 200-300 mesh smectite clay, or calcium carbonate having a particle size up to 12 microns. The coating can be applied through a brush or through a small orifice nozzle.
U.S. Pat. No. 4,221,697 discloses stable, fluid, moldable and curable compositions from which may be fabricated composite materials. The fluid compositions comprise a polymerizable organic liquid having a viscosity not greater than 50 poise at molding temperature and inorganic filler particles constituting at least 20% by volume and, optionally, up to 90% by volume.
U.S. Pat. No. 4,735,027 is merely noted for disclosing a coating for wallboard which does not crack or shrink as it drys.
Using a relatively coarse filler (average particle size about 75 to about 350 microns) together with a latex binder, a very high solids coating which is at least about 60% by volume in solids (about 80% by wt. or higher) can be made with a relatively low working viscosity (up to about 5,000 cps or less). Although thicknesses as low as about 1 mil can be used, these very high solids coatings can preferably be applied to obtain thick single layers (from about 0.010 to about 0.050 inches or even thicker) and oven cured without mudcracking (cracking due to shrinkage). These very high solids coatings can be applied in thick single layers. Acceptably the coatings can be from:about 1 to about 125 mils thick, and preferably it is in the range of from about 10 to about 75 mils thick. These coatings retain about 82% or more of their original wet. thickness upon oven curing.
This allows thick single coat applications not possible with typical lower solids coatings.
The resulting coating is extremely hard and durable. When applied to a relatively soft mineral fiber substrate, these coatings provide excellent impact resistance and abrasion resistance. Because of the relatively low working viscosity of these coatings, a number of application methods are possible, including spray coating. Furthermore, the coating can be spray coated at a low pressure of from about 10 to about 60 PSI (pounds per square inch).